• Korean Journal of Construction Engineering and Management
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• v.19 no.1
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• pp.74-79
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• 2018

The establishment of an effective bidding system is critical to ensure both the high quality of civil infrastructure and proper earning of contractors. However, the continuous changes of a bidding system in South Korea reveal that problems such as a dumping or high price winning have not been fully resolved yet. This study thus aims at understanding the bidding behavior and strategies of contractors by analyzing a tender ratio in historical data. Multiple regression analysis is conducted to understand the effect of internal and external factors (e.g., estimated cost, combined value of construction performance evaluation) on a tender ratio. The results statistically show that such factors affect the tender ratio an individual bidder determines and have the varying effect on the tender ratio by contractors' firm size.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.370-375
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• 2011

In this paper, as a follow-up PRT studies of "J. Lee & K. Kim[2]", in terms of public transportation systems, economic feasibility of PRT systems was investigated. Based on previous studies, PRT demand was estimated and the required number of PRT vehicles has been calculated and the benefit was estimated. To ensure the economic feasibility, construction cost of a PRT system should be the level of 8 billion won per km, and the annual operating costs of the PRT system construction should be approximately 4.63% level. As a result, how much to reduce PRT construction costs, depending on whether decisions are considered to be economically feasible. Thus, PRT technology development will be conducted by targeting the most lightweight and by minimizing the infrastructure and vehicles of PRT.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.31-36
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• 2005

In this paper, we propose a new optical switching system as a infrastructure of the BcN, in which the high traffic volume will be expected due to the multimedia service, like P2P services. Because the JET protocol, the most popular protocol in OBS (Optical Burst Switching) research area, has high blocking probability for burst, it prevents commercialization in real network for its low throughput in TCP layer. To improve high blocking rate in OBS network, we segment large network into small network and perform burst scheduling to avoid burst loss. By using proposed scheme, Internet provider can reduce network deployment cost in Metro network as well as large mesh core networks

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.12
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• pp.63-72
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• 2007

This paper addresses the system development that can transfer data and TDM signals simultaneously by adding TDM pseudowires functions to E-PON system. E-PON technology is one of many technologies which can realize FTTH, has raised as next generation access network solution having both low-cost Ethernet technology and optical infrastructure. TDM pseudowires service is the new voice/data conversion technology which can transfer the existing TDM circuit switched voice and data over packet switching network. In this paper, this system can provide both data and TDM service without deteriorating QoS by adding TDM pseudowires service module to E-PON, and then implementing QoS control function. Therefore, the competitive system which can transfer both data and TDM signal, can be installed.

• International journal of advanced smart convergence
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• v.4 no.2
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• pp.109-119
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• 2015

The interaction between wireless sensors such as Internet of Things (IoT) and Cloud is a new paradigm of communication virtualization to overcome resource and efficiency restriction. Cloud computing provides unlimited platform, resources, services and also covers almost every area of computing. On the other hand, Wireless Sensor Networks (WSN) has gained attention for their potential supports and attractive solutions such as IoT, environment monitoring, healthcare, military, critical infrastructure monitoring, home and industrial automation, transportation, business, etc. Besides, our virtual groups and social networks are in main role of information sharing. However, this sensor network lacks resource, storage capacity and computational power along with extensibility, fault-tolerance, reliability and openness. These data are not available to community groups or cloud environment for general purpose research or utilization yet. If we reduce the gap between real and virtual world by adding this WSN driven data to cloud environment and virtual communities, then it can gain a remarkable attention from all over, along with giving us the benefit in various sectors. We have proposed a Pub/Sub-based sensor virtualization framework Cloud environment. This integration provides resource, service, and storage with sensor driven data to the community. We have virtualized physical sensors as virtual sensors on cloud computing, while this middleware and virtual sensors are provisioned automatically to end users whenever they required. Our architecture provides service to end users without being concerned about its implementation details. Furthermore, we have proposed an efficient content-based event matching algorithm to analyze subscriptions and to publish proper contents in a cost-effective manner. We have evaluated our algorithm which shows better performance while comparing to that of previously proposed algorithms.

• Korean Journal of Childcare and Education
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• v.9 no.3
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• pp.189-207
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• 2013

This study was to examine current situations and factors related to private learning expenses. A household survey involving a nationally representative sample of 976 households and 1,648 3-5 year old children was conducted. The questionnaire was comprised of two parts; the first part investigated the demographic and socio-economic status of the parents. The second part inquired as to the type and cost of private education, during the month of June, 2012. Data were analyzed by chi-square, one-way ANOVA and multiple regression analyses. The findings of the study were: First, 86.7% of parents of pre-school children used private learning. Second, private learning expenses were estimated to be 129,700 Won for 3~5 year old children. And older children and children from higher income and full-time homemaker families used more private learning. Thirds, Income and the child's age affected private learning expenses. Policy measures were suggested based on the findings as follows: Institutional infrastructure should be established: Strong support for national curriculum and the development and dissemination of special programs is needed.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.4
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• pp.11-18
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• 2017

The Objective of this Study is to Prove the Effectiveness of a Smart Water Management(SWM) Technology. The SWM Technology can Reduce the Production Cost using Internet of Thing(IoT) Technology that Utilizes Remote Metering of Consumer's Water usage and Reduce the Leakage of Supply Facilities. The SWM Demonstration Model Installed a Remote Water Leakage Sensor, Smart Metering and Micro Multi Sensor in Water Supply Facility, and Provided Real-Time Monitoring of the Operation Status. Consumers can be Provided the usage of Tap Water and the Water Puality through a Smart Phone Application. At this Time, we Surveyed Whether Consumers save the Tap Water or Drinking Directly using the Tap Water usage Information. Also, this Study is to Verify the Degree of Improvement of Water Supply Rates and Drinking Water Rate, and to Decrease Consumer's Complaints, Operating Costs, and Water Consumption by the SWM Technology. It is also Established a SWM Model Combined with the IoT Sensor at Supply Facilities, operator monitoring system and explored recovery solution detected events. It means the upbringing of the domestic water industry by developing the related technologies and spreading the SWM to advanced levels.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.59-67
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• 2002

Recently, much demand of vector data have increased rapidly such as a digital map instead of traditional a paper map and the raster data such as a high-resolution orthoimage have been used for many GIS application with the advent of industrial high-resolution satellites and development of aerial optical sensor technologies. Aerial photogrammetric technologies using an airship can offer cost-effective and high-resolution color images as well as real time images, different from conventional remote sensing measurements. Also, it can acquire images easily and its processing procedure is short and simple relatively. On the other hand, it has often been used for the production of a small-scale land use map not required high accuracy, monitoring of linear infrastructure features through mosaicking strip images and construction of GIS data. Through this study, the developed aerial photogrammetric system using the airship expects to be applied to not only producing of scale 1:5, 000 digital map but also verifying, editing, and updating the digital map which was need to be reproduced. Further more, providing the various type of video-images, it expects to use many other GIS applications such as facilities management, scenery management and construction of GIS data for Urban area.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.101-110
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• 2011

Because bridges can cause more significant damage than other infrastructure a certain level of safety shall necessarily be secured for users. As most of bridges' service life become 20-30 years there will be a dramatic increase in the maintenance and repair cost but the budget and human resource will be limited. Asset management technique can help the efficiency in maintenance and budget management with the limited resource. For its application, there must be a way to evaluate how bridges provide service to users. The level of service can be quantified by a performance measure. This study introduces performance measures and an evaluation process for the determination of level of service. The evaluation results will be used as a fundamental information in the determination of maintenance/repair/management targets and in the decision making process of the bridge asset management.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.687-694
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• 2020

SDN and NFV are next-generation network technologies, and cloud, such as data centers, campuses, and large companies, has been established, or is actively applied by service-oriented communication companies. In particular, the Defense Integrated Data Center will be a prime example for military applications. In order for the Defense Integrated Data Center (DIDC) to become an intelligent center, it is accelerating the promotion of the "Smart Defense Integrated Data Center", which applied the latest information and communication technology (ICT). At the time of the establishment of DIDC, it plans to start building infrastructure such as cloud services at around 30% level, and expand D-Cloud to 75% through 'Cloud First'. In addition, the introduction of SDN/NFV will reduce the operation cost and manpower of DIDC, strengthen the ability to efficiently use information resources and cyber information protection systems, and increase flexibility and agility in using each system to improve efficiency in defense management in the future. Therefore, we will discuss the justification and expected effects of SDN/NFV introduction, focusing on DIDC.